i have made a way to assign the last number but on uploading it on spoj it says wrong answer . can anyone can help to sort out this problem. my code is:

include<iostream>

include<cmath>

using namespace std; int main() { short int t; cin>>t; if(t<=30) {while(t-- ) {short int a; short int r=0; long long int b,c; cin>>a>>b; if(a==0 && b==0) { break; } else if(b==0) { cout<<"1\n"; } else if(a==0) { cout<<"0\n"; } else { r=b%4; if(r==0) { c=a%2; if(c==0) cout<<"6\n"; else if(c==1) cout<<"1\n"; } else { c=pow(a,r); c=c%10; cout<<c<<endl; } } } } return 0; }